If you’re making outbound calls through Twilio and seeing “Spam Risk” or “Scam Likely” labels show up on your recipients’ phones, you’re not alone. It’s becoming increasingly common, especially with high-volume calling, newly purchased numbers, or unverified caller IDs.
The good news: it’s not random, and it’s not inevitable. Understanding why carriers flag calls and how to prevent it can make the difference between a 60% answer rate and a 15% answer rate.
Here’s what you need to know.
How carrier spam filters actually work
AT&T, Verizon, and T-Mobile don’t flag calls on their own. They rely on analytics engines from companies like Hiya, TNS, and First Orion to determine whether an outbound call looks risky.
These systems watch for patterns that scream “robocall”:
- High call volume from a single number
- Short call durations or immediate hang-ups
- Repetitive dialing to the same numbers
- Low answer rates or high complaint rates
Even legitimate business calls can trip these filters if your calling pattern looks automated. This is especially true for AI-powered systems that haven’t established reputation signals yet.
Think of it like email spam filters. Send 500 identical emails in an hour from a new domain, and you’re landing in spam folders. Phone calls work the same way now.
B2B vs. B2C: your spam risk varies
Consumer-facing (B2C) calls face aggressive filtering. Carriers are hyper-vigilant about anything that looks like mass consumer outreach, particularly under STIR/SHAKEN and TCPA regulations.
Business-to-business (B2B) calls have lower risk, provided you:
- Call during normal business hours (9am to 5pm in their timezone)
- Use caller ID that clearly identifies your company
- Maintain consistent, predictable calling patterns
The rule of thumb: the more your outbound behavior resembles human-driven business communication, the less likely it gets flagged.
How to reduce spam flagging (and stay compliant)
Here’s what actually works to maintain good number reputation and avoid “Spam Risk” labels.
1. Register your numbers with analytics databases
This is the single most important step. Register outbound numbers with:
- Free Caller Registry – Register with Hiya, TNS, First Orion
- Google Verified Calls
- Twilio Trust Hub
Registration tells carriers “this is a legitimate business number.” It won’t guarantee you never get flagged, but it’s the foundation of good caller reputation.
2. Use verified caller IDs (STIR/SHAKEN)
STIR/SHAKEN is the caller ID authentication framework required by the FCC. Using Twilio’s Trust Hub helps you achieve A-level attestation by verifying your business identity and number ownership.
A-level attestation means the carrier can cryptographically verify your call is legitimate and not spoofed. This dramatically reduces spam flags and can add a “Verified” checkmark on some devices.
B-level or C-level attestation? You’re much more likely to be flagged or blocked.
3. Avoid patterns that look like spam
Carriers penalize behavior that resembles robocalling:
- Don’t flood calls from a single number (stay under 100-150 calls per day per number)
- Rotate responsibly across a pool of verified numbers
- Maintain normal call durations (under 30 seconds looks suspicious)
- Pace your calls like a human would (no rapid-fire dialing)
If you need to make 500 calls per day, use 5-10 numbers instead of hammering one number.
4. Monitor your number reputation actively
Use tools like:
- CallerID Reputation or NumVerify to check spam scores
- Twilio Trust Hub Insights to track flagging incidents
If a number gets flagged, retire it immediately and register a replacement. One flagged number can hurt your entire operation’s reputation.
5. Warm up new numbers gradually
New numbers with zero calling history are suspicious to carriers. Start small:
- Week 1: 10-20 calls per day
- Week 2: 30-50 calls per day
- Week 3+: Scale to your target volume
This builds reputation signals that tell carriers “this is a real business, not a spam operation.”
Think of it like warming up an email domain. You wouldn’t send 10,000 emails on day one from a brand-new domain. Same principle here.
6. Be transparent in caller ID and opening scripts
Set your caller ID to something recognizable. “AgentVoice Support” or “ABC Company” works. “Unknown” or a random number doesn’t.
Open every call with a clear brand introduction:
“Hi, this is Sarah from AgentVoice calling about your recent inquiry.”
This reduces spam complaints and hang-ups, which directly impact your reputation score.
How AgentVoice can help you avoid spam flags
AgentVoice can automate the technical heavy lifting for you:
- Registers your outbound numbers via Twilio Trust Hub
- Enables STIR/SHAKEN attestation for verified caller ID
- Dynamically rotates numbers across campaigns and regions
- Monitors for spam flags and can automatically replace affected numbers
- Maintains proper call pacing to avoid carrier penalties
The result: higher connection rates, cleaner outreach, and stronger brand credibility.
The bigger picture
Spam labeling isn’t just a technical nuisance. It’s a reputation problem that directly impacts your revenue.
As AI voice agents become more capable and realistic, carriers and regulators are paying closer attention to call authenticity, consent, and transparency. A “Spam Risk” label can cut your answer rates in half. Multiple flagged numbers can get your entire Twilio account flagged or suspended.
By combining verified caller registration, responsible automation practices, and regulatory awareness, you stay ahead of both the algorithms and the evolving rulebook.
The businesses winning with AI voice aren’t cutting corners. They’re building trust signals into every call.
Compliance checklist
Want a complete compliance checklist? We’re putting together an “AI voice compliance checklist (2025)” covering FCC requirements, TCPA rules, and Twilio verification workflows. Drop your email below and we’ll send it over when it’s ready.
In the meantime, start with these three actions:
- Register your numbers at freecallerregistry.com today
- Enable STIR/SHAKEN through Twilio Trust Hub
- Audit your calling patterns (volume, pacing, answer rates)
Getting flagged as spam is preventable. Most businesses just don’t know the rules until it’s too late.